
Postgres FM
A weekly podcast about all things PostgreSQL
Latest episodes

May 31, 2024 • 32min
Sponsoring the community
Michael is joined by Claire Giordano, Head of Postgres Open Source Community Initiatives at Microsoft, to discuss several ways to contribute to the Postgres community — from core contributions, to extensions, to events, and (of course) podcasts. Here are some links to things they mentioned:What’s new with Postgres at Microsoft (blog post by Claire) https://techcommunity.microsoft.com/t5/azure-database-for-postgresql/what-s-new-with-postgres-at-microsoft-2024-edition/ba-p/4140085 Citus https://github.com/citusdata/citus Fibonacci Spirals and 21 Ways to Contribute to Postgres Beyond Code (talk by Claire) https://archive.fosdem.org/2020/schedule/event/postgresql_fibonacci_spirals_and_21_ways_to_contribute_to_postgres_beyond_code/ How to contribute to PostgreSQL or, 50 Ways To Love Your Project (talk slides by Josh Berkus) https://berkus.org/pdf_presos/50_ways.pdf pgconf dot dev https://2024.pgconf.dev/ POSETTE: An Event for Postgres https://www.citusdata.com/posette About Talk Selection for POSETTE https://www.citusdata.com/blog/2024/04/22/about-talk-selection-for-posette-an-event-for-postgres-2024/ Claire’s video about how to say Postgres, PostgreSQL, Citus, and a few questionably named Microsoft things https://x.com/clairegiordano/status/1503784151614320640 Citus goes fully open source https://www.citusdata.com/blog/2024/04/22/about-talk-selection-for-posette-an-event-for-postgres-2024/Contributor Profiles https://www.postgresql.org/community/contributors/ Mastodon post by Álvaro Herrera (of EDB) https://lile.cl/@alvherre/112444579030481334 Talking Postgres podcast (formerly called Path To Citus Con): https://talkingpostgres.com/~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is produced by:Michael Christofides, founder of pgMustardNikolay Samokhvalov, founder of Postgres.aiWith special thanks to:Jessie Draws for the elephant artwork

May 24, 2024 • 50min
Full text search
Nikolay and Michael discuss full text search in Postgres — some of the history, some of the features, and whether it now makes sense to try to replace or combine it with semantic search. Here are some links to things they mentioned:Full Text Search https://www.postgresql.org/docs/current/textsearch.htmltsearch2 https://www.postgresql.org/docs/9.6/tsearch2.htmlDictionaries https://www.postgresql.org/docs/current/textsearch-dictionaries.html RUM index https://github.com/postgrespro/rum Okapi BM25 https://en.wikipedia.org/wiki/Okapi_BM25 tf–idf https://en.wikipedia.org/wiki/Tf%E2%80%93idf unaccent https://www.postgresql.org/docs/current/unaccent.html tsvector and tsquery https://www.postgresql.org/docs/current/datatype-textsearch.html GiST indexes https://www.postgresql.org/docs/current/gist.html GIN indexes https://www.postgresql.org/docs/current/gin.html Controlling Text Search (including setweight function) https://www.postgresql.org/docs/current/textsearch-controls.html pg_trgrm https://www.postgresql.org/docs/current/pgtrgm.html btree_gist https://www.postgresql.org/docs/current/btree-gist.html btree_gin https://www.postgresql.org/docs/current/btree-gin.html websearch_to_tsquery https://www.postgresql.org/docs/current/textsearch-controls.html#TEXTSEARCH-PARSING-QUERIES pgvector https://github.com/pgvector/pgvector Our previous episode on search https://postgres.fm/episodes/search ~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork

May 17, 2024 • 40min
Minor releases
Nikolay and Michael discuss Postgres minor releases — how the schedule works, options for upgrading to them, and the importance of reading the release notes. Here are some links to things they mentioned:PostgreSQL 16.3, 15.7, 14.12, 13.15, and 12.19 released (announcement) https://www.postgresql.org/about/news/postgresql-163-157-1412-1315-and-1219-released-2858/ PostgreSQL versioning policy https://www.postgresql.org/support/versioning/ PostgreSQL 14.4 release notes (most recent minor release not on the usual schedule) https://www.postgresql.org/docs/release/14.4/ Minor release roadmap https://www.postgresql.org/developer/roadmap/ Our last episode on upgrades (major and minor) https://postgres.fm/episodes/upgrades All versions of Postgres https://bucardo.org/postgres_all_versions.html Why upgrade? (Useful tool by depesz) https://why-upgrade.depesz.com/ Stop and start Postgres faster https://postgres.fm/episodes/stop-and-start-postgres-faster WAL and checkpoint tuning https://postgres.fm/episodes/wal-and-checkpoint-tuning Postgres CVE-2024-4317 and how to fix the system views (5 mins of Postgres by Lukas Fittl) https://youtube.com/watch?v=fLwVvJ3fKdA Our episode on NULL https://postgres.fm/episodes/nulls-the-good-the-bad-the-ugly-and-the-unknown What should we do for episode 100? https://www.reddit.com/r/PostgreSQL/comments/1cn8ajh/what_should_we_do_for_episode_100_of_postgres_fm/ ~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork

May 10, 2024 • 29min
Custom vs generic plan
Nikolay and Michael discuss custom and generic planning in prepared statements — how it works, how issues can present themselves, some ways to view the generic plan, and some benefits of avoiding planning (not just time). Here are some links to things they mentioned:PREPARE https://www.postgresql.org/docs/current/sql-prepare.html track_activity_query_size https://www.postgresql.org/docs/current/runtime-config-statistics.html#GUC-TRACK-ACTIVITY-QUERY-SIZE plan_cache_mode https://www.postgresql.org/docs/current/runtime-config-query.html#GUC-PLAN-CACHE-MODE EXPLAIN (GENERIC_PLAN) https://www.postgresql.org/docs/current/sql-explain.html#id-1.9.3.148.8 EXPLAIN (GENERIC_PLAN) in PostgreSQL 16 (blog post by Laurenz from Cybertec) https://www.cybertec-postgresql.com/en/explain-generic-plan-postgresql-16/ Running EXPLAIN on any query, even with $1 parameters (blog post and video by Lukas Fittl of pganalyze) https://pganalyze.com/blog/5mins-postgres-explain-generic-plan EXPLAIN from pg_stat_statements, how to get the generic plan (blog post by Franck Pashto of Yugabyte) https://dev.to/yugabyte/explain-from-pgstatstatements-normalized-queries-how-to-always-get-the-generic-plan-in--5cfi Rework query relation permission checking (commit by Amit Langote) https://git.postgresql.org/gitweb/postgres.git?p=postgresql.git;a=commit;h=a61b1f74823c9c4f79c95226a461f1e7a367764b Partition pruning, prepared statements and generic vs custom query plans (a follow up blog post and video by Lukas) https://pganalyze.com/blog/5mins-postgres-partition-pruning-prepared-statements-generic-vs-custom-query-plans Our episode on over-indexing (inc LWLock discussion) https://postgres.fm/episodes/over-indexing “The year of the lock manager’s revenge” (from blog post by Jeremy Schneider) https://ardentperf.com/2024/03/03/postgres-indexes-partitioning-and-lwlocklockmanager-scalability/ ~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork

May 3, 2024 • 45min
LIMIT vs Performance
Nikolay and Michael discuss LIMIT in Postgres — what it does, how it can help with performance, and an interesting example where adding it can actually hurt performance(!) Here are some links to things they mentioned:LIMIT considered harmful in PostgreSQL (Twitter thread by Christophe Pettus) https://twitter.com/Xof/status/1413542818673577987 LIMIT and OFFSET (docs) https://www.postgresql.org/docs/current/queries-limit.html No OFFSET (by Markus Winand) https://use-the-index-luke.com/no-offset LIMIT clause (docs) https://www.postgresql.org/docs/current/sql-select.html#SQL-LIMIT ~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork

Apr 26, 2024 • 36min
Buffers II (the sequel)
Nikolay and Michael return to the topic of using the buffers explain parameter — with a new analogy, some (conspiracy) theories of why it's still not on by default, and some related chat about the serialize parameter coming in 17. Here are some links to things they mentioned:BUFFERS by default (episode 4) https://postgres.fm/episodes/buffers-by-default Lightning talk by Michael at pgDay Paris (5 mins) https://www.youtube.com/watch?v=WfY-mSpUzaQ&t=1470s Waiting for SERIALIZE https://www.depesz.com/2024/04/11/waiting-for-postgresql-17-invent-serialize-option-for-explain/ ~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork

Apr 19, 2024 • 44min
Massive DELETEs
Nikolay and Michael discuss doing massive DELETE operations in Postgres — what can go wrong, how to prevent major issues, and some ideas to minimise their impact. Here are some links to things they mentioned:Article based on Nikolay’s talk, including batching implementation (translated to English) https://habr-com.translate.goog/en/articles/523536/?_x_tr_sl=ru&_x_tr_tl=en&_x_tr_hist=true Our episode on WAL and checkpoint tuning https://postgres.fm/episodes/wal-and-checkpoint-tuningEgor Rogov’s book on Postgres Internals (chapter 10 on WAL) https://edu.postgrespro.com/postgresql_internals-14_en.pdf full_page_writes https://www.postgresql.org/docs/current/runtime-config-wal.html#GUC-FULL-PAGE-WRITES TRUNCATE https://www.postgresql.org/docs/current/sql-truncate.html Our episode on partitioning https://postgres.fm/episodes/partitioning Our episode on bloat https://postgres.fm/episodes/bloat Our episode on index maintenance https://postgres.fm/episodes/index-maintenance ~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork

Apr 12, 2024 • 38min
Logical replication common issues
Nikolay and Michael are joined by Sai Srirampur, CEO and Co-founder of PeerDB, to discuss how to overcome several logical replication issues. They discuss the protocol versions, minimising slot growth, minimising lag, and some tips and tricks for scaling things well. Here are some links to things they mentioned:PeerDB https://www.peerdb.io/Our episode on logical replication https://postgres.fm/episodes/logical-replicationExploring versions of the Postgres logical replication protocol (blog post by Sai) https://blog.peerdb.io/exploring-versions-of-the-postgres-logical-replication-protocol Logical Streaming Replication Protocol https://www.postgresql.org/docs/current/protocol-logical-replication.htmlREPLICA IDENTITY FULL https://www.postgresql.org/docs/current/sql-altertable.html#SQL-ALTERTABLE-REPLICA-IDENTITYOn the performance impact of REPLICA IDENTITY FULL in Postgres (blog post by Xata) https://xata.io/blog/replica-identity-full-performance max_slot_wal_keep_size https://www.postgresql.org/docs/current/runtime-config-replication.html#GUC-MAX-SLOT-WAL-KEEP-SIZE Active Active in Postgres 16 (blog post by Crunchy Data) https://www.crunchydata.com/blog/active-active-postgres-16 pgEdge https://www.pgedge.com/DistSQL (term used by Mark Callaghan) https://smalldatum.blogspot.com/2023/07/keeping-up-with-sql-dbms-market.html Five tips on Postgres logical decoding (blog post by Sai) https://blog.peerdb.io/five-tips-on-postgres-logical-decodingPG Slot Notify: Monitor Postgres Slot Growth in Slack (blog post by PeerDB) https://blog.peerdb.io/pg-slot-notify-monitor-postgres-slot-growth-in-slack~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork

Apr 5, 2024 • 45min
Don't do this
Nikolay and Michael discuss several "Don't do this" lists about Postgres — picking out their favourite items, as well as some contentious ones that could be clearer, or not included. Here are some links to things they mentioned:Don’t do this (PostgreSQL wiki page) https://wiki.postgresql.org/wiki/Don't_Do_ThisHow to get into trouble using some Postgres features (how to by Nikolay) https://github.com/postgres-ai/postgres-howtos/blob/main/0016_how_to_get_into_trouble_using_some_postgres_features.mdDon’t do this (jOOQ list) http://www.jooq.org/doc/3.19/manual/reference/dont-do-thisDon’t use NOT IN (jOOQ) https://www.jooq.org/doc/3.19/manual/reference/dont-do-this/dont-do-this-sql-not-in/ Our episode about NULLs https://postgres.fm/episodes/nulls-the-good-the-bad-the-ugly-and-the-unknown Our episode on timestamps https://postgres.fm/episodes/timestamps~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork

Mar 29, 2024 • 42min
Search
Nikolay and Michael have a high-level discussion on all things search — touching on full-text search, semantic search, and faceted search. They discuss what comes in Postgres core, what is possible via extensions, and some thoughts on performance vs implementation complexity vs user experience. Here are some links to things they mentioned:Simon Riggs https://www.linkedin.com/feed/update/urn:li:activity:7178702287740022784/Companion databases episode https://postgres.fm/episodes/companion-databasespgvector episode https://postgres.fm/episodes/pgvectorFull Text Search https://www.postgresql.org/docs/current/textsearch.htmlSemantic search https://en.wikipedia.org/wiki/Semantic_searchFaceted search https://en.wikipedia.org/wiki/Faceted_searchFaceting large result sets in PostgreSQL https://www.cybertec-postgresql.com/en/faceting-large-result-sets/RUM index https://github.com/postgrespro/rum Hybrid search (Supabase guide) https://supabase.com/docs/guides/ai/hybrid-search Elastic https://www.elastic.co/ GiST indexes https://www.postgresql.org/docs/current/gist.html GIN indexes https://www.postgresql.org/docs/current/gin.html btree_gist https://www.postgresql.org/docs/current/btree-gist.html btree_gin https://www.postgresql.org/docs/current/btree-gin.html pg_trgrm https://www.postgresql.org/docs/current/pgtrgm.html Text Search Types (tsvector and tsquery) https://www.postgresql.org/docs/current/datatype-textsearch.html Postgres full text search with the “websearch” syntax (blog post by Adam Johnson) https://adamj.eu/tech/2024/01/03/postgresql-full-text-search-websearch/Understanding Postgres GIN Indexes: The Good and the Bad (blog post by Lukas Fittl) https://pganalyze.com/blog/gin-index ParadeDB https://www.paradedb.com/ ZomboDB https://www.zombodb.com/ Introduction to Information Retrieval (book by Manning, Raghavan, and Schütze) https://www.amazon.co.uk/Introduction-Information-Retrieval-Christopher-Manning/dp/0521865719 How to build a search engine with Ruby on Rails (blog post by Justin Searls) https://blog.testdouble.com/posts/2021-09-09-how-to-build-a-search-engine-with-ruby-on-rails/~~~What did you like or not like? What should we discuss next time? Let us know via a YouTube comment, on social media, or by commenting on our Google doc!~~~Postgres FM is brought to you by:Nikolay Samokhvalov, founder of Postgres.aiMichael Christofides, founder of pgMustardWith special thanks to:Jessie Draws for the amazing artwork